Is Sulpher Coated Urea Organic?

We are growing blueberries in 6-6.5 pH clay laom and I would like to lower the pH of the soil, but we are trying to keep our garden organic. Is sulpher coated urea considered organic? Pine needles and coffee grounds seem to be ineffective in getting the pH below 6. Would you have any suggestions for a fertilizer that would lower the pH and still be organic?

Yes, it is organic. It is considered a slow release organic fertilizer. Diluted vinegar is a great, quick way to do it. It won't last long term, but can give it a shot while you wait for other methods to take effect. Use 2 tbls per 1 gallon of water and water the plants with it once a week. It's not technically a fertilizer, but can be used in conjunction with your regular fertilizing schedule. If you have not read it, this article will be helpful: https://www.gardeningknowhow.com/edible/fruits/blueberries/lower-soil-ph-blueberries.htm